So Momo is a computer with legs, right?
Then why is she consuming text data through a massively inefficient optical method? She could just jack an eBook into her skull and have processed it in half a femptosecond.
Because she's an
artificial intelligence, not a computer with legs.
The acquisition of knowledge takes more than a simple upload of information--that's one of the many things that bothered me about
The Matrix. Our body of knowledge is not only that which we learn, but also the experience of learning it--including, significantly, our response to it.
Part of it has to do with the basic storage functions of the brain--as we experience any given stimuli, we highlight certain elements, diminish others, and organize the important ones according to the pre-existing structure of our minds (which structure may also be altered by the incoming information). Our memories are created by association with pre-existing memories; the more connections to existing memories and concepts that a new experience enjoys, the more easily-accessible and important that new memory will be (this is also why there are so many triggers for those ridiculous little embarrassing memories that make you want to stab yourself in the head with a fork when there's no logical reason for you to have remembered them--there's a lot of psychological energy devoted to them, and every single detail is linked to everything it can be). Memory and knowledge are, basically, like doing a wikislide inside your brain.
That said, the intake process has to be slowed down, or else, instead of establishing those connections, even for a being like Momo, with her increased mental capacity, it would be more like the eight hundred public-domain classic novels we all have sitting on our hard drives--often in .txt format from the early days of the internet--just waiting for us to finally read the damn things, as we've been promising ourselves we intend to do for many, many years.
That said, the real answer is probably just that, if she had done an instant upload, as you suggest, Jeph would have had to express that in some visual way that didn't look like Momo was possessed by some sort of electronic demon, to say nothing of ignoring the disconnect between the time necessary for such an upload and the extra time we meat-based comic readers need to upload the same information into our tiny meat-brains. Also, she's reading a book instead of a tablet or some similar device for the same reason the save icon in a variety of programs is a 3.5" floppy disc: it's a symbol that has been culturally accepted as having a particular socially-constant meaning, thus providing artists a shorthand for conveying that meaning.
tl;dr: Unicorns like to poop in the woods, which is why gnomes wear hats.